Metadata

Introduction

An experimental tool for extracting and validating DC metadata encoded as XHTML meta elements.

dcmeta

• XSLT stylesheet
  Parameters:
  • $page = URL of XHTML doc
  • $profile = URL of profile
  • $xslstyle = URL of XSLT stylesheet
  • $cssstyle = URL of CSS stylesheet for output
• Sample profile files:
  • simpledc.xml : 15 DC elements optional, repeatable; no element refinements; no encoding schemes.
  • qualifieddc.xml : all DC elements and element refinements optional, repeatable; DC-registered encoding schemes optional.
  • mydc.xml : application-specific constraints on elements permitted, cardinality, encoding schemes.
• CSS stylesheet for output
• Client-side Javascript bookmarklet for IE
• DOS .BAT file for Saxon

Examples

• Sample input
• Outputs:
  • checked against simpledc profile
  • checked against qualifieddc profile
  • checked against mydc profile

Structure of Profile File

A "profile" is a set of rules which specifies:

• which DC metadata elements and element refinements are permitted (e.g. only the 15 elements or some subset of the larger set of elements and element refinements);
• minimum/maximum permitted occurrences of a specified property (e.g. metadata should include exactly one occurrence of DC.Title)
• "encoding schemes" permitted for a property (e.g. DC.Subject properties should carry scheme = "LCSH")
• permitted values for a property, even in the absence of an encoding scheme (e.g. DC.Publisher should have the value "UKOLN")

A profile is a simple XML document containing:

• a "root" XML element my:elements where the namespace prefix is associated with the XML Namespace Name http://www.ukoln.ac.uk/metadata/dcmeta/.
• a sequence of child XML elements named my:element, each corresponding to a metadata element permitted by the profile

Each my:element element must have the following child elements:

• a my:prefix element, the content of which is either "DC" or "DCTERMS";
• a my:name element, the content of which is the name of the metadata element as used following the prefix in the name attribute of the (X)HTML meta element;
  dcmeta is permissive regarding the case of the names used in metadat instances. e.g. it accepts both "DC.title" and "DC.Title" as occurrences of the same metadata element. However it will display a warning where the case differs from the name specified in the profile.
• a my:minoccurs element, the content of which is an integer indicating the minimum number of occurrences of this element required in a metadata instance;
• a my:maxoccurs element, the content of which is an integer indicating the maximum number of occurrences of this element permitted in a metadata instance (or the string "unbounded", if an unlimited number of occurrences are permitted).

Each my:element element may have the following additional child elements:

• a my:schemes element, which acts as a container element for one or more my:scheme elements, representing permitted Encoding Schemes for values of this metadata element.
  N.B. to indicate that the use of an Encoding Scheme is optional for values of a metadata element, you must include an Encoding Scheme of "[None]". If the profile specifies a list of Encoding Schemes without an entry for "[None]", then one of those Encoding Schemes must be used in metadata instances;
• a my:fixedvalues element, which acts as a container element for one or more my:fixedvalue elements, representing a set of possible values for this metadata element, even where an Encoding Scheme is not specified.
  (This is to permit the checking of values which it is expected will be constrained in a particular context e.g. it may be desirable to check that for all the documents on a single Web site, the value of DC.Publisher is constant.

Examples from Profile Files

Example 1

<?xml version="1.0" encoding="UTF-8"?>

<my:elements xmlns:my="http://www.ukoln.ac.uk/metadata/dcmeta/">

  <my:element>
    <my:prefix>DC</my:prefix>
    <my:name>title</my:name>
    <my:minoccurs>0</my:minoccurs>
    <my:maxoccurs>unbounded</my:maxoccurs>
  </my:element>

</my:elements>

The DC.title element is optional and may be repeated an unlimited number of times. No encoding schemes are permitted, and there is no checking of the values of the DC.title element.

Example 2

<?xml version="1.0" encoding="UTF-8"?>

<my:elements xmlns:my="http://www.ukoln.ac.uk/metadata/dcmeta/">

  <my:element>
    <my:prefix>DC</my:prefix>
    <my:name>subject</my:name>
    <my:minoccurs>0</my:minoccurs>
    <my:maxoccurs>unbounded</my:maxoccurs>
    <my:schemes>
      <my:scheme><my:schemename>[None]</my:schemename></my:scheme>
      <my:scheme><my:schemename>LCSH</my:schemename></my:scheme>
      <my:scheme><my:schemename>MESH</my:schemename></my:scheme>
      <my:scheme><my:schemename>DDC</my:schemename></my:scheme>
      <my:scheme><my:schemename>LCC</my:schemename></my:scheme>
      <my:scheme><my:schemename>UDC</my:schemename></my:scheme>
    </my:schemes>
  </my:element>

</my:elements>

The DC.subject element is optional and may be repeated an unlimited number of times. Five encoding schemes are permitted, but the "[None]" entry means that the use of an encoding scheme is not mandatory.

Example 3

<?xml version="1.0" encoding="UTF-8"?>

<my:elements xmlns:my="http://www.ukoln.ac.uk/metadata/dcmeta/">

  <my:element>
    <my:prefix>DC</my:prefix>
    <my:name>subject</my:name>
    <my:minoccurs>1</my:minoccurs>
    <my:maxoccurs>unbounded</my:maxoccurs>
    <my:schemes>
      <my:scheme><my:schemename>LCSH</my:schemename></my:scheme>
    </my:schemes>
  </my:element>

</my:elements>

The DC.subject element is mandatory and may be repeated an unlimited number of times. Values must be associated with the LCSH encoding scheme.

Example 4

<?xml version="1.0" encoding="UTF-8"?>

<my:elements xmlns:my="http://www.ukoln.ac.uk/metadata/dcmeta/">

  <my:element>
    <my:prefix>DC</my:prefix>
    <my:name>publisher</my:name>
    <my:minoccurs>1</my:minoccurs>
    <my:maxoccurs>1</my:maxoccurs>
    <my:schemes>
      <my:scheme><my:schemename>[None]</my:schemename></my:scheme>
    </my:schemes>
    <my:fixedvalues><my:fixedvalue>UKOLN</my:fixedvalue></my:fixedvalues>
 </my:element>

</my:elements>

The DC.publisher element is mandatory and may only occur once. No encoding scheme is valid, and only one value is permissible.

Example 5

<?xml version="1.0" encoding="UTF-8"?>

<my:elements xmlns:my="http://www.ukoln.ac.uk/metadata/dcmeta/">

  <my:element>
    <my:prefix>DC</my:prefix>
    <my:name>type</my:name>
    <my:minoccurs>1</my:minoccurs>
    <my:maxoccurs>1</my:maxoccurs>
    <my:schemes>
      <my:scheme>
        <my:schemename>DCMIType</my:schemename>
        <my:schemevalues>
          <my:schemevalue>Collection
          <my:schemevalue>Dataset
          <my:schemevalue>Event
          <my:schemevalue>Image
          <my:schemevalue>Interactive Resource
          <my:schemevalue>Service
          <my:schemevalue>Software
          <my:schemevalue>Sound
          <my:schemevalue>Text
          <my:schemevalue>Physical Object
        </my:schemevalues>
      </my:scheme>
    </my:schemes>
 </my:element>

</my:elements>

The DC.type element is mandatory and may only occur once. Values must use the DCMIType encoding scheme and must be drawn from the enumerated list.